1. Login to Acquire with your credentials.
2. Click on the Proposals button.
3. Either click an existing proposal to open it or click HERE to learn how to add a new proposal option.
4. Next to the Details click one of the options.
5. In the Line Items row, press the + button.
6. This will bring up your Pricebook item list. You can scroll or use the search feature to pick out an item, or even multiple items. If selecting more than 1, you will see a checkbox to the left of the item, and the item will be shaded blue. You can select as many items as you'd like and they will all get added at once. When done, tap the 'Add' button on the bottom right of the screen to add these to the invoice.
7. Finally, you will need to press the Save button, in the upper right-hand corner
This video may be helpful as well video